x0.s

这是一个符合posix.13 pse51的实时内核

/* Project: 	HARTIK 3.0      				*/
/* Description:	Hard Real TIme Kernel for 386 & higher machines */
/* Author:	Gerardo Lamastra				*/
/* Date:	9/5/96 						*/
/* Revision:	2.0						*/


/* The first things to do when an X application starts :	*/
/* Set up segment registers & stack; then execute startup code	*/
/* When the application returns the gate-jmp make us return to	*/
/* RM through X interface!					*/

/* Use X standard GDT selectors */
#include "sel.h"

#ifndef __LINUX__
.extern __startup 
.extern __stkbase 
.extern __stktop
#else
.extern _startup 
.extern _stkbase 
.extern _stktop
#define __stkbase _stkbase
#define __stktop  _stktop
#define __startup _startup
#endif

.data

base:
.space 	8129,0
tos:

.text

.globl	start
.globl _start

_start:
start:		movw	$(PM_APPLDATA_SEL),%ax
		movw	%ax,%ds
		movw	%ax,%es
		movw	%ax,%ss
		movw	$(X_FLATDATA_SEL),%ax
		movw	%ax,%fs
		movl	$tos,%esp
		
		#ifdef __DEBUG__
		/* A Brown o should appear... */
		    pushw	%gs
		    movw	$(X_VIDEO_SEL),%ax
		    movw	%ax,%gs
		    movl	$158,%edi
		    movb	$'1',%gs:0(%edi)
		    incl	%edi
		    movb	$6,%gs:0(%edi)
		    popw	%gs
		#endif

		movl	$base,__stkbase
		movl	$tos,__stktop
		
		cld		
		call __startup 
		
		.byte	0x0EA		   /* Direct gate jmp */
		.long	0
		.word	X_RM_BACK_GATE